6 files changed, 119 insertions, 87 deletions

diff --git a/crates/base_db/src/lib.rs b/crates/base_db/src/lib.rs
index 5f77a0b1f..980a0ed98 100644
--- a/crates/base_db/src/lib.rs
+++ b/crates/base_db/src/lib.rs
@@ -59,6 +59,8 @@ pub trait CheckCanceled {
         Self: Sized + panic::RefUnwindSafe,
         F: FnOnce(&Self) -> T + panic::UnwindSafe,
     {
+        // Uncomment to debug missing cancellations.
+        // let _span = profile::heartbeat_span();
         panic::catch_unwind(|| f(self)).map_err(|err| match err.downcast::<Canceled>() {
             Ok(canceled) => *canceled,
             Err(payload) => panic::resume_unwind(payload),
@@ -68,6 +70,7 @@ pub trait CheckCanceled {
 
 impl<T: salsa::Database> CheckCanceled for T {
     fn check_canceled(&self) {
+        // profile::heartbeat();
         if self.salsa_runtime().is_current_revision_canceled() {
             Canceled::throw()
         }
diff --git a/crates/ide/src/doc_links.rs b/crates/ide/src/doc_links.rs
index 9301cdeff..99276168f 100644
--- a/crates/ide/src/doc_links.rs
+++ b/crates/ide/src/doc_links.rs
@@ -98,6 +98,29 @@ pub(crate) fn remove_links(markdown: &str) -> String {
     out
 }
 
+/// Retrieve a link to documentation for the given symbol.
+pub(crate) fn external_docs(
+    db: &RootDatabase,
+    position: &FilePosition,
+) -> Option<DocumentationLink> {
+    let sema = Semantics::new(db);
+    let file = sema.parse(position.file_id).syntax().clone();
+    let token = pick_best(file.token_at_offset(position.offset))?;
+    let token = sema.descend_into_macros(token);
+
+    let node = token.parent()?;
+    let definition = match_ast! {
+        match node {
+            ast::NameRef(name_ref) => NameRefClass::classify(&sema, &name_ref).map(|d| d.referenced(sema.db)),
+            ast::Name(name) => NameClass::classify(&sema, &name).map(|d| d.referenced_or_defined(sema.db)),
+            _ => None,
+        }
+    };
+
+    get_doc_link(db, definition?)
+}
+
+/// Extracts all links from a given markdown text.
 pub(crate) fn extract_definitions_from_markdown(
     markdown: &str,
 ) -> Vec<(Range<usize>, String, Option<hir::Namespace>)> {
@@ -178,15 +201,15 @@ pub(crate) fn resolve_doc_path_for_def(
 ) -> Option<hir::ModuleDef> {
     match def {
         Definition::ModuleDef(def) => match def {
-            ModuleDef::Module(it) => it.resolve_doc_path(db, &link, ns),
-            ModuleDef::Function(it) => it.resolve_doc_path(db, &link, ns),
-            ModuleDef::Adt(it) => it.resolve_doc_path(db, &link, ns),
-            ModuleDef::Variant(it) => it.resolve_doc_path(db, &link, ns),
-            ModuleDef::Const(it) => it.resolve_doc_path(db, &link, ns),
-            ModuleDef::Static(it) => it.resolve_doc_path(db, &link, ns),
-            ModuleDef::Trait(it) => it.resolve_doc_path(db, &link, ns),
-            ModuleDef::TypeAlias(it) => it.resolve_doc_path(db, &link, ns),
-            ModuleDef::BuiltinType(_) => None,
+            hir::ModuleDef::Module(it) => it.resolve_doc_path(db, &link, ns),
+            hir::ModuleDef::Function(it) => it.resolve_doc_path(db, &link, ns),
+            hir::ModuleDef::Adt(it) => it.resolve_doc_path(db, &link, ns),
+            hir::ModuleDef::Variant(it) => it.resolve_doc_path(db, &link, ns),
+            hir::ModuleDef::Const(it) => it.resolve_doc_path(db, &link, ns),
+            hir::ModuleDef::Static(it) => it.resolve_doc_path(db, &link, ns),
+            hir::ModuleDef::Trait(it) => it.resolve_doc_path(db, &link, ns),
+            hir::ModuleDef::TypeAlias(it) => it.resolve_doc_path(db, &link, ns),
+            hir::ModuleDef::BuiltinType(_) => None,
         },
         Definition::Macro(it) => it.resolve_doc_path(db, &link, ns),
         Definition::Field(it) => it.resolve_doc_path(db, &link, ns),
@@ -328,28 +351,6 @@ fn rewrite_url_link(db: &RootDatabase, def: ModuleDef, target: &str) -> Option<S
         .map(|url| url.into_string())
 }
 
-/// Retrieve a link to documentation for the given symbol.
-pub(crate) fn external_docs(
-    db: &RootDatabase,
-    position: &FilePosition,
-) -> Option<DocumentationLink> {
-    let sema = Semantics::new(db);
-    let file = sema.parse(position.file_id).syntax().clone();
-    let token = pick_best(file.token_at_offset(position.offset))?;
-    let token = sema.descend_into_macros(token);
-
-    let node = token.parent()?;
-    let definition = match_ast! {
-        match node {
-            ast::NameRef(name_ref) => NameRefClass::classify(&sema, &name_ref).map(|d| d.referenced(sema.db)),
-            ast::Name(name) => NameClass::classify(&sema, &name).map(|d| d.referenced_or_defined(sema.db)),
-            _ => None,
-        }
-    };
-
-    get_doc_link(db, definition?)
-}
-
 /// Rewrites a markdown document, applying 'callback' to each link.
 fn map_links<'e>(
     events: impl Iterator<Item = Event<'e>>,
diff --git a/crates/ide/src/syntax_highlighting/inject.rs b/crates/ide/src/syntax_highlighting/inject.rs
index 963c3fb59..b62d43256 100644
--- a/crates/ide/src/syntax_highlighting/inject.rs
+++ b/crates/ide/src/syntax_highlighting/inject.rs
@@ -11,7 +11,8 @@ use syntax::{
 };
 
 use crate::{
-    doc_links::extract_definitions_from_markdown, Analysis, HlMod, HlRange, HlTag, RootDatabase,
+    doc_links::{extract_definitions_from_markdown, resolve_doc_path_for_def},
+    Analysis, HlMod, HlRange, HlTag, RootDatabase,
 };
 
 use super::{highlights::Highlights, injector::Injector};
@@ -190,7 +191,7 @@ pub(super) fn doc_comment(
                         extract_definitions_from_markdown(line)
                             .into_iter()
                             .filter_map(|(range, link, ns)| {
-                                Some(range).zip(validate_intra_doc_link(sema.db, &def, &link, ns))
+                                Some(range).zip(resolve_doc_path_for_def(sema.db, def, &link, ns))
                             })
                             .map(|(Range { start, end }, def)| {
                                 (
@@ -283,33 +284,6 @@ fn find_doc_string_in_attr(attr: &hir::Attr, it: &ast::Attr) -> Option<ast::Stri
     }
 }
 
-fn validate_intra_doc_link(
-    db: &RootDatabase,
-    def: &Definition,
-    link: &str,
-    ns: Option<hir::Namespace>,
-) -> Option<hir::ModuleDef> {
-    match def {
-        Definition::ModuleDef(def) => match def {
-            hir::ModuleDef::Module(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::Function(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::Adt(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::Variant(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::Const(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::Static(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::Trait(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::TypeAlias(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::BuiltinType(_) => None,
-        },
-        Definition::Macro(it) => it.resolve_doc_path(db, &link, ns),
-        Definition::Field(it) => it.resolve_doc_path(db, &link, ns),
-        Definition::SelfType(_)
-        | Definition::Local(_)
-        | Definition::GenericParam(_)
-        | Definition::Label(_) => None,
-    }
-}
-
 fn module_def_to_hl_tag(def: hir::ModuleDef) -> HlTag {
     let symbol = match def {
         hir::ModuleDef::Module(_) => SymbolKind::Module,
diff --git a/crates/profile/src/hprof.rs b/crates/profile/src/hprof.rs
index 014e906e6..5fdb37206 100644
--- a/crates/profile/src/hprof.rs
+++ b/crates/profile/src/hprof.rs
@@ -69,6 +69,20 @@ pub fn span(label: Label) -> ProfileSpan {
     }
 }
 
+#[inline]
+pub fn heartbeat_span() -> HeartbeatSpan {
+    let enabled = PROFILING_ENABLED.load(Ordering::Relaxed);
+    HeartbeatSpan::new(enabled)
+}
+
+#[inline]
+pub fn heartbeat() {
+    let enabled = PROFILING_ENABLED.load(Ordering::Relaxed);
+    if enabled {
+        with_profile_stack(|it| it.heartbeat(1));
+    }
+}
+
 pub struct ProfileSpan(Option<ProfilerImpl>);
 
 struct ProfilerImpl {
@@ -92,6 +106,28 @@ impl Drop for ProfilerImpl {
     }
 }
 
+pub struct HeartbeatSpan {
+    enabled: bool,
+}
+
+impl HeartbeatSpan {
+    #[inline]
+    pub fn new(enabled: bool) -> Self {
+        if enabled {
+            with_profile_stack(|it| it.heartbeats(true))
+        }
+        Self { enabled }
+    }
+}
+
+impl Drop for HeartbeatSpan {
+    fn drop(&mut self) {
+        if self.enabled {
+            with_profile_stack(|it| it.heartbeats(false))
+        }
+    }
+}
+
 static PROFILING_ENABLED: AtomicBool = AtomicBool::new(false);
 static FILTER: Lazy<RwLock<Filter>> = Lazy::new(Default::default);
 
@@ -105,6 +141,7 @@ struct Filter {
     depth: usize,
     allowed: HashSet<String>,
     longer_than: Duration,
+    heartbeat_longer_than: Duration,
     version: usize,
 }
 
@@ -121,6 +158,7 @@ impl Filter {
         } else {
             Duration::new(0, 0)
         };
+        let heartbeat_longer_than = longer_than;
 
         let depth = if let Some(idx) = spec.rfind('@') {
             let depth: usize = spec[idx + 1..].parse().expect("invalid profile depth");
@@ -131,7 +169,7 @@ impl Filter {
         };
         let allowed =
             if spec == "*" { HashSet::new() } else { spec.split('|').map(String::from).collect() };
-        Filter { depth, allowed, longer_than, version: 0 }
+        Filter { depth, allowed, longer_than, heartbeat_longer_than, version: 0 }
     }
 
     fn install(mut self) {
@@ -143,9 +181,15 @@ impl Filter {
 }
 
 struct ProfileStack {
-    starts: Vec<Instant>,
+    frames: Vec<Frame>,
     filter: Filter,
     messages: Tree<Message>,
+    heartbeats: bool,
+}
+
+struct Frame {
+    t: Instant,
+    heartbeats: u32,
 }
 
 #[derive(Default)]
@@ -157,35 +201,49 @@ struct Message {
 
 impl ProfileStack {
     fn new() -> ProfileStack {
-        ProfileStack { starts: Vec::new(), messages: Tree::default(), filter: Default::default() }
+        ProfileStack {
+            frames: Vec::new(),
+            messages: Tree::default(),
+            filter: Default::default(),
+            heartbeats: false,
+        }
     }
 
     fn push(&mut self, label: Label) -> bool {
-        if self.starts.is_empty() {
+        if self.frames.is_empty() {
             if let Ok(f) = FILTER.try_read() {
                 if f.version > self.filter.version {
                     self.filter = f.clone();
                 }
             };
         }
-        if self.starts.len() > self.filter.depth {
+        if self.frames.len() > self.filter.depth {
             return false;
         }
         let allowed = &self.filter.allowed;
-        if self.starts.is_empty() && !allowed.is_empty() && !allowed.contains(label) {
+        if self.frames.is_empty() && !allowed.is_empty() && !allowed.contains(label) {
             return false;
         }
 
-        self.starts.push(Instant::now());
+        self.frames.push(Frame { t: Instant::now(), heartbeats: 0 });
         self.messages.start();
         true
     }
 
     fn pop(&mut self, label: Label, detail: Option<String>) {
-        let start = self.starts.pop().unwrap();
-        let duration = start.elapsed();
+        let frame = self.frames.pop().unwrap();
+        let duration = frame.t.elapsed();
+
+        if self.heartbeats {
+            self.heartbeat(frame.heartbeats);
+            let avg_span = duration / (frame.heartbeats + 1);
+            if avg_span > self.filter.heartbeat_longer_than {
+                eprintln!("Too few heartbeats {} ({}/{:?})?", label, frame.heartbeats, duration)
+            }
+        }
+
         self.messages.finish(Message { duration, label, detail });
-        if self.starts.is_empty() {
+        if self.frames.is_empty() {
             let longer_than = self.filter.longer_than;
             // Convert to millis for comparison to avoid problems with rounding
             // (otherwise we could print `0ms` despite user's `>0` filter when
@@ -198,6 +256,15 @@ impl ProfileStack {
             self.messages.clear();
         }
     }
+
+    fn heartbeats(&mut self, yes: bool) {
+        self.heartbeats = yes;
+    }
+    fn heartbeat(&mut self, n: u32) {
+        if let Some(frame) = self.frames.last_mut() {
+            frame.heartbeats += n;
+        }
+    }
 }
 
 fn print(
diff --git a/crates/profile/src/lib.rs b/crates/profile/src/lib.rs
index 79dba47d5..9ca6341db 100644
--- a/crates/profile/src/lib.rs
+++ b/crates/profile/src/lib.rs
@@ -10,7 +10,7 @@ mod tree;
 use std::cell::RefCell;
 
 pub use crate::{
-    hprof::{init, init_from, span},
+    hprof::{heartbeat, heartbeat_span, init, init_from, span},
     memory_usage::{Bytes, MemoryUsage},
     stop_watch::{StopWatch, StopWatchSpan},
 };
diff --git a/docs/user/manual.adoc b/docs/user/manual.adoc
index b1beeb883..e74b287fb 100644
--- a/docs/user/manual.adoc
+++ b/docs/user/manual.adoc
@@ -254,23 +254,10 @@ let g:LanguageClient_serverCommands = {
 
 ==== YouCompleteMe
 
-1. Install YouCompleteMe by following the instructions
-  https://github.com/ycm-core/lsp-examples#rust-rust-analyzer[here]
+Install YouCompleteMe by following the instructions
+  https://github.com/ycm-core/YouCompleteMe#installation[here].
 
-2. Configure by adding this to your vim/neovim config file (replacing the existing Rust-specific line if it exists):
-+
-[source,vim]
-----
-let g:ycm_language_server =
-\ [
-\   {
-\     'name': 'rust',
-\     'cmdline': ['rust-analyzer'],
-\     'filetypes': ['rust'],
-\     'project_root_files': ['Cargo.toml']
-\   }
-\ ]
-----
+rust-analyzer is the default in ycm, it should work out of the box.
 
 ==== ALE